This invention relates to a fuel injection nozzle assembly with improved response for internal combustion engines.
The fuel injection nozzle assembly of pressure accumulation type which has so far been installed on engines comprises a needle valve located in the nozzle body and biased downwardly by the force of a compression spring, the tip of the needle valve being adapted to close spray orifices. Further, the needle valve has mounted thereon at its upper end a check valve adapted to close a fuel supply port. The arrangement is made such that when fuel under high pressure is supplied into this fuel supply port the check valve will open to allow the fuel under high pressure to flow into the nozzle body, and further when the pressure of the fuel within the nozzle body overcomes the force of the compression spring biasing the needle valve downwardly the needle valve will move upwards thereby opening the spray orifices and enabling the fuel to be injected through the latter into the cylinder. However, the fuel injection nozzle assembly of such a construction has been disadvantageous in that, because the needle valve supports the check valve, the mass of the needle valve is large, and therefore the response of it is poor because of its large inertia at the time of opening and closing the spray orifices, and also the durability of it is low because of its long overall length.